2: niAChR agonists and antagonists

Question 0

Hexamethonium

Answer 0

Ganglion blocker - blocks all parasympathetic and sympathetic nn
6C chain + Double positive charge - administered by injection
Blocks the channel pore

Question 1

Nicotine

Answer 1

Ganglionic AChR agonist, less potent at nmj
Depolarising block (binds, activates, and then removed slowly)

Question 2

Atracurium

Answer 2

Competitive antagonist at the nmj causing non depolarising blockade
Quaternary ammonium compound
Block end plate potential caused by both nervous stimulation and direct administration of neurotransmitters
Tetanic fade due to block of positive feedback autoreceptors
Ester - broken down spontaneously and by plasma eat erases
Affect white muscle faster than red muscle - useful in anaesthesia

Question 3

Pancuronium

Answer 3

Competitive antagonist at the nmj causing non depolarising blockade
Quaternary ammonium compound
Block end plate potential caused by both nervous stimulation and direct administration of neurotransmitters
Tetanic fade due to block of positive feedback autoreceptors
Longer action than atracurium - no hydrolysis
Affect white muscle faster than red muscle - useful in anaesthesia

Question 4

Suxamethonium

Answer 4

Selective depolarising blocker at the nmj
Phase 1: enhanced depol and spastic paralysis.
potentiated by anti-AChEs, opposed by atracurium
Phase II: remains blocking receptors. Flaccid paralysis.
reversed by anti-AChEs
Used for intubation. Short action as broken down by BuChE.

Question 5

Muscarine

Answer 5

Non selective Muscarinic ACh receptor agonist

Question 6

Mecamylamine

Answer 6

Non selective, non competitive nAChR antagonist

Used as an antihypertensive